Consumer accessible refrigerated appliances include cooling systems to refrigerate products such as canned or bottled beverages for purchase by consumers. The cooling systems are designed to maintain the interior of these appliances (and the products therein) within a predefined temperature range. Typically, a consumer accessible refrigerated appliance (herein appliance) has a door (generally glass) that is opened by either sliding the door to a side of the appliance or rotating the door about a hinged axis to gain access to the products therein. Such appliances are commonly referred to in the industry as reach-in coolers, slide coolers, or visi-coolers, for example.
It is not uncommon for the door of an appliance to remain ajar after it has been opened. When this occurs, the temperature within the appliance rises and often, even though running continuously, the cooling system is unable to cool the interior of the appliance much below the ambient temperature of the air surrounding the appliance. Thus, the cooling system wastes a large amount of power in attempting to cool the interior of the appliance with the interior of the appliance having essentially the same temperature as it would have if the cooling system were off. In addition, continuously running the cooling system may result in condensation freezing on the evaporator coils of the cooling system, thereby further reducing the efficiency of the cooling system.
Additionally, the cooling system of an appliance typically maintains the interior of the appliance within the predefined temperature range regardless of usage. Thus, the refrigerated appliance may consume a great deal of power/energy maintaining products therein at a low temperature even when there is no demand for the product. For example, if the appliance is located in a grocery store that is closed at night, the appliance will consume power to keep the product cool even though no one will be purchasing the product at those times.
Further, the cooling system of the appliance typically transitions the cooling system between two modes based on one or more absolute temperature set points. In a first mode of operation (e.g., a cooling needed mode), a compressor and an evaporator fan are both ON to lower the temperature to a predetermined low set point. In a second mode of operation (e.g., a no cooling needed mode), the compressor is OFF and the evaporator fan remains ON while the temperature is allowed to raise to a predetermined high set point. Thus, the evaporator fan is always ON to circulate air within the appliance. In addition to circulating air, however, the evaporator fan introduces heat, which must then be removed through operation of the compressor.